1. Field
The present embodiment relates to a semiconductor memory and a system using a semiconductor memory.
2. Description of the Related Art
In recent years, portable electronic devices (mobile phones, digital cameras, and so on) driven by using a battery have come into wide use. Low power consumption is strongly required of a semiconductor memory used in a system of a portable electronic device in order to enable long-term use of the battery. Japanese Laid-open Patent Publication No. H09-147559 discloses a sense amplifier that amplifies a signal read to one of a bit line pair from a memory cell selected by a word line selection operation, by using precharge voltage of the other of the bit line pair as reference voltage.
Japanese Laid-open Patent Publication No. H09-147559 discloses that, where the amplification operation of the sense amplifier is divided into two stages, the bit line used for obtaining the reference voltage in the bit line pair is separated from the sense amplifier in synchronization with the start of the second-stage amplification operation.